"Why is the human skull as dense as it is? Nowadays we can send a message around the world in one-seventh of a second, but it takes years to drive an idea through a quarter-inch of human skull."

“We think we are smart because we have been flying for about sixty years. Birds and bees and butterflies have been flying for hundreds of thousands of years.”

“There are two kinds of courage. One is a spontaneous explosion of aroused instincts to meet some sudden emergency; the other is steadfast and enduring against repeated failures and rebuffs. It's what boxers call 'the fighting heart,' the will to come bouncing back every time one is knocked down. All pioneers need that kind of courage, and our youngsters will need plenty of it when the plunge into the world of tomorrow.”

“You know, you read about the future. You can't help that. I don't look upon the future. I am not a politician. I am not worried about the future at all. I don't like to run it down. I don't like to think of it being too dark because I expect to spend all the rest of my life there and I don't want to have a nasty end to it.”

“The key to economic prosperity is the organized creation of dissatisfaction.”

“We find that in research a certain amount of intelligent ignorance is essential to progress; for, if you know too much, you won't try the thing.”

“A problem thoroughly understood is always fairly simple. Found your opinions on facts, not prejudices. We know too many things that are not true.”